This invention relates to climate control in motor vehicles in general and more particularly to a control mechanism for use in a heating or air conditioning system with a rear seat air supply system, the mechanism independently controlling the air distribution in the rear seat area.
A conventional heating or air conditioning system with a rear seat air supply system is disclosed in U.S. Pat. No. 4,586,652. In that system, air is conveyed from a blower unit through an evaporator and thence is conducted, in accordance with the position of an air flap, directly to the passenger compartment as cool air or, by passing it through a heat exchanger, as warm air. The mixture ratio of warm air to cool air can be adjusted by an air-temperature setting element on a front-seat control unit in the front-seat area of the passenger compartment.
The system includes a front-seat air-mix chamber in the front-seat area of the passenger compartment. The front-seat outlet area of the front-seat air-mix chamber is trifurcated in the conventional manner into a defroster air duct, a front seat foot air duct and a median-plane air duct (which leads to one or several vents, preferably in the dashboard).
Three other ducts are connected to the front-seat air mix chamber. The first connects the front-seat air-mix chamber with the outlet side of the evaporator, the second connects the chamber with the inlet side of the heat exchanger, and the third with the outlet side of the heat exchanger. The inlet to the heat exchanger inlet duct is provided with a front air flap to control the flow of cool air into the inlet side of the head exchanger and the inlet to the heat exchanger outlet duct is provided with a front-seat air-mix flap to control the proportion of warm and cool air entering the front-seat air-mix chamber.
The latter two ducts also connect the heat exchanger inlet and outlet with a rear-seat air-mix chamber. These ducts terminate in a common mouth at the entrance to the rear-seat air-mix chamber. By means of a rear-seat air-mix flap on the common mouth of these two ducts, the cool air flow to the rear-seat area from the inlet side of the heat exchanger can be completely blocked, independently of a rear-seat control, or can be admixed in part with the warmed air from the outlet side of the heat exchanger.